Monday, May 30, 2011

Fun with footnotes, today at AVRPI!! You'll remember that a couple of summers ago, a study by Churchill et al. (2009) tried to argue that the cut marks on a rib from the Shanidar 3 Neanderthal were the result of a wound inflicted by a modern human on that poor sap. Naturally, the science press had a field day with this, although several commentators argued that the evidence presented by Churchill and co. had been stretched way too thin, and that there really was no way to know who (what?) had killed Shanidar 3.

I just finished reading a paper by Trinkaus and Buzhilova (in press) on the death of the Sunghir 1. Sunghir 1 was an old man dating to the Early Gravettian (somewhere b/w 28-24kya) who was buried with an extremely lavish set of grave goods, including ornaments comprising several thousands of mammoth ivory beads, ivory bracelets, a schist pendant and a lot of red ochre spread over the entire burial. There is no question that this is one of the most remarkable Upper Paleolithic burials know.

How does that relate to Shanidar 3, you ask? Well, beyond the fact that Shanidar 3 has been argued to be an intentional burial, Trinkaus and Buzhilova report that, during a renewed inventory of the Sunghir 1 remains undertaken in 2009 which included a careful cleaning of the remains, they identified "an oblique defect, medial-caudal to lateral-cranial, on the left ventral corner of the body" of the Sunghir 1 first thoracic vertebra (T1). I'll return to the details of the Sunghir 1 injury in an upcoming post, but suffice it to say here that they are able to show that the lesion is indicative of a wound inflicted by a sharp implement and that would have been lethal to Sunghir 1.

OK, so returning to our dead homies Neanderthals, this study provides the third most ancient case of a weapon-inflicted wound leading to the death of a Paleolithic forager, the other two being Saint-Cesaire 1 and Shanidar 3, in decreasing order of age. Both of these have been described by Churchill et al. (2009) has resulting from inter-specific violence by modern humans on Neanderthals. However, Trinkaus and Buzhilova argue that "[i]n neither of them is there sufficient evidence, given current geochronology and available technology to meaningfully hypothesize intergroup aggression.". Their justification for this different assessment is then provided in one of the most epic and detailed footnotes I've come across, which I quote in full here:

Churchill et al. (2009) have argued that the injuries to Shanidar 3 and Saint-Césaire 1 are likely to have been perpetrated on these Neandertals by early modern humans. They argue for probable regional sympatry of Shanidar 3 with early modern humans in southwest Asia and certain sympatry for Saint- Césaire 1 in western Europe and superior projectile technology among early modern humans with respect to the Middle Paleolithic Shanidar 3. However, their argument, despite caveats, requires distortions of the relevant geochronology, misrepresentation of the available technology, and special pleading. In western Europe, there is no evidence for (presumably modern human associated) Aurignacian levels stratified below those of the (Neandertal associated) Châtelperronian (Bordes, 2003; Zilhão et al., 2006), as it is at Saint-Césaire (Lévêque et al., 1993), and all of the reliable dates place the Châtelperronian prior to the Aurignacian (Zilhão & d’Errico, 2003). The one radiometric date for the Saint-Césaire Châtelperronian level, a TL date (36 300±2700 cal BP) (Mercier et al., 1991), has a sufficiently large standard error to make it inappropriate to date the burial relative to Châtelperronian or Aurigiacian levels in the region. There is therefore no evidence, either paleontological or by assuming that the earliest Aurignacian was made by modern humans, that there were modern humans in western Europe at the time of Saint-Césaire 1. Churchill et al.’s assessment of the relative ages of Shanidar 3 and early modern humans in southwest Asia confuses radiocarbon and calendar years and makes unwarranted assumptions of who was responsible for which technocomplex; a reassessment of the available dates for diagnostic human remains, plus the stratigraphic position of Shanidar 3, clarifies the chronology. Shanidar 3 derives from near the top of Level D of Shanidar Cave, but stratigraphically well below the radiocarbon dates of ~47 and ~51 ka 14C BP (~51 and ~56ka cal BP) (Trinkaus, 1983). The youngest Middle Paleolithic modern humans within southwest Asia (at Qafzeh and Skhul) are MIS 5c in age (~90–100 ka cal BP) (Valladas et al., 1988; Stringer et al., 1989), and hence much older. Modern human remains do not reappear in southwest Asia until at least 35 ka 14C BP (~40 ka cal BP) (Bergman & Stringer, 1989), ~15 000 years later. In the Zagros the Baradostian technocomplex, the more recent phases of which are associated with modern humans (Scott & Marean, 2009), is dated to ~36 ka 14C BP (~41 ka cal BP) (Otte & Kozlowski, 2007). In addition, contra Shea & Sisk (2010), there are no diagnostic human remains associated with the eastern Mediterranean littoral IUP, that is ~35 ka 14C BP (~40 ka cal BP); Qafzeh 1 and 2 are undated, Ksar Akil 1 is younger, and the few IUP Üçağızlı teeth may well be Neandertals (Neuville, 1951; Bergman & Stringer, 1989; Gulec et al., 2007). One must go to equatorial Africa to find roughly contemporaneous modern humans (Haile-Selassie et al., 2004). With respect to technology, either Châtelperronian or Aurignacian lithics could have inflicted the frontal wound on Saint-Césaire 1. Although Middle Paleolithic spears appear to have mostly had relatively thick lithic points (Shea, 2006), thinner tools capable of producing the Shanidar 3 injury are represented in the Shanidar (and southwest Asian) Middle Paleolithic (Skinner, 1965). Moreover, one has to go to southern Africa to find evidence for contemporaneous ‘advanced’ projectile weaponry (Shea, 2006; Lombard & Phillipson, 2010; but see comments and caveats in Villa & Soriano (2010) and Lombard & Phillipson (2010)). Therefore, contra Churchill et al. (2009), the Shanidar and Saint Césaire Neandertals had the technology available to inflict their respective wounds, and there is no evidence (direct or indirect) for synchronous and sympatric modern humans. It is inappropriate to infer that individuals responsible for the Shanidar 3 and Saint-Césaire1 injuries were other than Neandertals." (Trinkaus and Buzhilova, in press: 7).

So, in a nutshell, there is no good reason to assume that the wounds sustained by Shanidar 3 were inflicted by modern humans. In fact, all of the available evidence points to Shanidar 3 having lived at a moment when only Neanderthals were kicking around the Zagros, and that they had access to technology that could well have left the mark found on the Shanidar 3 ribs.

Why does this matter? Well, for one thing, setting the record straight on this destroys any evidence for the interactions between Neanderthals and modern humans having been strictly inimical and violent. For another, it provides up a fascinating and heretofore underappreciated glimpse into the range of interpersonal relations Neanderthals could have had with other Neanderthals. Given the tendency by many to see Neanderthal behavior has homogeneous and monotonous, emphasizing that their interactionswith others of their kind were occasionally violent to the point of being lethal contributes to showing them to have been all too humans in certain respects.

Friday, May 06, 2011

How's this for an inspirational story? A professor suffering from terminal cancer insisted on giving his current students their last lecture, even though he'd be hospitalized, so he did it via Skype, hospital gown, tubes and all. Hard not to be moved moved by Prof. Kielhorn's dedication to his students and his teaching.

At 79, Kielhorn was just one class short of finishing 45 years of teaching without missing a single day.With his perfect attendance at risk, Kielhorn reminded his oncologist at Good Shepherd Medical Center in Longview, Texas: "I have class tomorrow at 3 o'clock." That's when his daughter, Martha Croft, and granddaughter, Courtney Bellamy, came up with a plan and started making arrangements for Kielhorn to give his last class via teleconference from the hospital. "Either we were going to break him out or they were going to bring the Skype in," Croft said with a laugh.

45 years of teaching without missing a single class? So much for university professors not giving a damn about students and/or teaching. That kind of devotion to university education is incredible, and something to aspire to. I for one already can't claim that distinction, so hats off to you, sir!

Last week, I mentioned that scientists - in this case, specifically anthropologists - need to develop strategies to better control the narratives about their research that get circulated in popular media. To me, the need to do so is spurred by both the public interest in anthropological research as well as the need to make science relevant, interesting and exciting to a broader swath of society than it currently is. I also think that scientists have a duty to reach out to the public and talk about what it is they do and why it matters. Really, we need to be able to do this no matter how narrow and specialized our specific field on inquiry. In part, I feel it's the minimum we can do considering the amount of public funding most of us get for our research. As well, if we hope to get the public excited about the scientific inquiry and kids about careers in science, making efforts and taking steps to reach broader audiences should not only be commendable, it should be a professional imperative.

The fine folks at Scientific American seem to be thinking along very similar lines. Under the aegis of the Nature Publishing Group, they're spearheading an effort called "1,000 Scientists in 1,000 Days" that "aims to help with all of those goals by making it easier for scientists and teachers to connect. The idea is simple. We seek scientists who are willing to volunteer to advise on curricula, answer a classroom's questions, or visit a school." They have a sign-up sheet for interested scientists - including a category specifically for anthropologists! - and they'll take care of matching interested parties with interested schools in their area. Sounds like a win-win to me, and you only have to volunteer as much as you are comfortable or able to. Get to it, folks!

Wednesday, May 04, 2011

A few months ago, Henry et al. (2011a) published a truly remarkable study that analyzed the phytoliths and starch grains that had gotten encrusted in the dental calculus (i.e., plaque) of three Neanderthal individuals, two from the site of Spy (Belgium), and another from the site of Shanidar (Iraq). Their study provided the first direct evidence that plant foods were an integral part of the Neanderthal diet by identifying phytoliths (the microscopic silicate 'skeletons' of plant parts that are unique to each plant species) of date palms in the calculus of Shanidar III, and starch grains attributed to various species of wild barley and legumes. The Spy I and II specimens yielded no phytoliths, but did yield starch grains that indicate they consumed water lily corms as well as some variety of sorghum and five other types of plants. The fact that these plant microfossils were found on the teeth of both Spy specimens is a strong indicator that these plants were part of the diet of that group as a whole, too. And the fact that Neanderthals from such distinct ecological settings preserve direct evidence of plant consumption suggests that it was a widespread dietary behavior, an observation that contrasts markedly with the 'Neanderthals as super-carnivore' idea that's been growing in the literature.

As if that wasn't enough, however, some of the starch grains found in the calculus of Shanidar III also had a peculiar morphology ("partly gelatinized") that matched that of experimental cooked barley starch grains. Further, Henry et al. (2011:487) observe that "The overall pattern of damage to the starch grains matches most closely with that caused by heating in the presence of water, such as during baking or boiling, rather than “dryer” forms of cooking like parching or popping (38). The finding of cooked Triticeae [barley] starches on the Shanidar teeth reinforces evidence from other studies that suggest that Near Eastern Neanderthals cooked plant foods." In other words, not only can we tell that Neanderthals cooked some of the plants they consumed, we can even get an idea of how they cooked them, most likely through boiling or baking. To me, this is doubly (triply?) neat because it also tells us something about the cooking technology this very likely required, namely some kind of cooking vessel, made out of either leather or wood.

However, Collins and Copeland (2011) now have a letter in press at PNAS that argues that Henry et al. (2011a) did not properly account for alternative manners in which starch grains can become partly gelatinized through various forms of diagenesis, that is post-depositional chemical or physical alteration, or what we commonly think of as decomposition. This diagenesis could have been triggered by both the presence of water in the cave sediments and/or their exposure to high heat.

I'm happy that PNAS actually gave Henry et al. (2011b) a chance to respond to this letter at the same time. In their reply, they point out, first, that the heat and humidity required to prompt 'spontaneous' gelatinization would be extremely unlikely to be present in cave sediment. They also indicate that complementary analyses of starch grains on stone tools from some of the same contexts from which teeth associated with altered starch grains are not altered, in contrast to what would be expected if these processes were affecting whole archaeological layers. Specifically, it suggests that lithics were used to process uncooked plant matter that was then cooked and later consumed by Neanderthals. Overall, the evidence therefore continues to indicate that Neanderthals not only ate plants, but also cooked them to both facilitate their consumption and increase their nutritiousness.

Tuesday, May 03, 2011

Science has a post on their website about a little study (Gillespie et al. 2009) that came out a couple of years ago that applied some Editor's Selection Iconkey biogeographical principles to provide a prediction of where Osama bin Laden might have been hiding. The paper was discussed in Scientific Americanwhen if first came out, but now has received a ton of attention because the authors' predicted hiding place for bin Laden ended up being only 268km away from the large compound in Abbottabad where he was dispatched by a team of US Navy SEALS a couple of days ago.

The principles that underpinned Gillespie et al.'s study are actually fairly straightforward. First, organisms tend to stay closest to areas that they are comfortable in (taken here to be the area immediately around Tora Bora). Second, within those area, organisms tend to concentrate on larger 'islands' where propitious conditions are found - in this case, it meant cities where individuals can be more inconspicuous, on top of having access to the amenities needed for both hiding and coordinating further action. Lastly, within such islands, organisms will tend to map onto localities that can support their life history characteristics, in this case the size of bin Laden's entourage and the physical space and specific resources they would need to be able to thrive.

A lot of the comments on the Science page and other places are critical of the study, saying it wasn't, in fact, very precise, and saying its findings have been misrepresented. Fair enough. But what's really interesting is that the study was still correct enough to identify the region, the kind of place (i.e., a city) and the kind of structure (a large-ish compound, not a cave!) where bin Laden was found. To focus on the fact that they didn't identify the exact city is to miss the broader point here: biogeography is useful to predict the kinds of areas that given organisms will be found in, and usually not pinpoint exact locations, though informed suggestions as to these can certainly be made. The authors' suggestion that bin Laden would be found hiding in a city within one of the provinces or FATAs (federally administered tribal areas) closest to Tora Bora (which was bin Laden's last reported position according to outside sources) basically proved correct. Detractors will say that this is so general as to be useless, but if you think about how you would structure the use of resources to track an individual in such a large region, you could do a lot worse than that as a starting point to develop a plan of action.

Now, you may well be asking why the hell am I talking about bin Laden and biogeography on this blog which usually focuses on archaeology and paleoanthropology. Well, that's because biogeography is becoming increasingly used in paleoanthropological research to map out areas that would have been best suited for the needs of various kinds of past hominin communities. Specifically, ecological niche modeling has been used to reconstruct the preferred habitats of given species or industries (Banks et al. 2006). This is done specifically by extrapolating from the ecological contexts in which given sites have been recovered what would have been the preferred ecological conditions for the hominins responsible for accumulating them. An example of this is a paper in which the potential extent of various Upper Paleolithic bifacial tools was inferred based on where they have been found over the past 150 years or so of research (Banks et al. 2009). Some members of the same team have also used this approach to reconstruct what the preferred habitats of Neanderthals and early European modern humans (Banks et al. 2010). In this case, they were able to suggest that the ecological niches most prized by both groups of hominins would have overlapped to a very large degree, implying that the two would have likely come into direct contact, leading to a situation whereby modern humans probably drove Neanderthals to extinction through some form of competitive exclusion.

Ecological niche modeling yields very interesting and though-provoking results, but it remains a means to en end, a tool rather than a be-all-end-all kind of approach. As in most models dependent on inputted information, the quality of the patterns it generates is constrained by the quality of the empirical data used in the first place. This was best demonstrated by a recent paper by Lozier et al. (2009) in which they used georeferenced sightings of sasquatch drawn from the Bigfoot Field Researchers Organization website to extrapolate the eoclogical niche and most likely range of that cryptozoid in western North America (as an aside, do check out the BFRO website, for a good look into how organized modern cryptozoology can be - and while you're there, since this week's my birthday, consider ordering a BFRO polo shirt for me!). The paper yields a convincing map of where sasquatch are most likely to be found... a distribution, which incidentally corresponds almost exactly to the modeled ecological niche of brown bears, providing one explanation for what many (if not all) sasquatch sightings may actually have really been of.

The point here is that you can model the ecological niche of any georeferenced dataset, so you need to amke sure your data are really appropriate for the question you're trying to answer. Just because you get an output doesn't mean you necessarily had reliable data on which to base it in the first place. This is a good example of the issues related to the GIGO problem (reconceptualized for non-computer scientists by M. Wolpoff here). In the case of modern humans and Neanderthals, this means specifically that you're limited to dated sites with good provenience information, which captures only part of the relevant sites. It also means that you're basing a species-level attribution on lithic assemblages, which is notoriously problematic (e.g., Clark and Riel-Salvatore 2006).

This is also true for biogeographic approaches in general, and especially as they are applied to people, who have broader sets of motivations than most other animals. Returning to 'where in the world is was Osama bin Laden', this means that to be as precise a predictive model as possible, the Gillespie et al. paper should have considered things like the distribution of religious groups in the various areas they proposed (Haider 2009). From my perspective, it's clear that the predictive potential of Gillespie et al.'s study would have been enhanced had they also considered anthropological and cultural geographic factors to make this a true study in human biogeography. For instance Haider (2009) specifically argued that it's unlikely that a Sunni Muslim like bin Laden would have sought refuge in Parachinar, which is a mostly Shiite city. On the other hand, guess which large city in the radius originally proposed by Gillespie et al. is found in a mostly Sunni province? That's right, Abbottabad. Obviously, there are others, but it goes to show that by explicitly incorporating social factors, biogeographic studies focused on humans can be that much more precise.

Edit 05/05/2011: Whoa - this has been the most popular post ever on this little blog! It was even picked as one of this week's ResearchBlogging 'Editor's Selection'. The moral of all this: obviously, I need to write about terrorism and Sasquatch a lot more frequently!

Monday, May 02, 2011

So, it's kind of a silly comic, definitely good for a few chuckles. Yet, when you take a second to think about it, there's a lot packed into it. In two little panels, the cartoonist manages to bring up two of the biggest misconceptions about prheistoric hunter-gatherers: 1) that hunter-gatherers spend only a small amount of time a day foraging for food and have an abundance of leisure time to devote to other pursuits; and 2) that modern humans actively killed off Neanderthals.

Now while some people still believe that confrontational, violent interactions occurred at least some of the time when modern humans and Neanderthals crossed paths (e.g., Mellars 2005), faithful AVRPI readers will know by now that this view not only glosses over a ton of inconvenient evidence, but also doesn't really jive with what we know about how groups of hunter-gatherers really compete with one another (cf. O'Connell 2006).

The first component, though - the 4-5 hours of work thing - is more interesting. It taps into a now outgrown view of hunter-gatherers as having comparatively easy lives, where only a few hours a day were spent procuring food. This idea derives from the notion of the "original affluent society" first promulgated by M. Sahlins during the Man the Hunter conference (Sahlins 1968). That conference was held in Chicago in 1966 and was published as an edited volume by the same name in 1968 (Lee and de Vore 1968). Using some of the data on foraging returns that Lee had collected, Sahlins argued that foragers like the Kalahari San groups only spent a few hours a day foraging for food, spending the rest of their time gossiping or involved in assorted leisure activities.

This was pretty revolutionary for the time. Up to that point, hunter-gatherers had been seen by most anthropologists as perpetually living difficult, physically demanding lives and as always living on the brink of starvation. Sahlins' perspective, on top of having a catchy name, was the perfect foil to that traditional view, on top of providing a view of 'people closer to nature' as living what was in many ways possibly a better life than 20th post-industrial Westerners that fit in well with some of the counter-culture ideas in vogue at the time.

However, in spite of its conceptual and socio-political sexiness, the 'original affluent society' was just as unrealistic a view as that of perpetually hungry foragers. For one thing, it was based on observations made on a handful of forager societies, and even if it had been true for them, it would have been unwarranted to transpose it to all hunter-gatherers in all times and places. Second, Sahlins ignored the fact that several hours were also employed processing the food resources gathered in the 2-4 hours he saw as a typical work day for hunter-gatherers. Thorough reviews and criticisms of the OAS model include those written by Bird-David (1992:26-28) and Kelly (1995:15-19).

Anyhoo, all of this to say that, in addition to being funny on the face of it, this little comic is doubly funny to the informed reader, since it also capitalizes (maybe unwittingly) on two anthropological idea that have very much outlived their original usefulness.

Sunday, May 01, 2011

A little while ago, someone contacted me asking if there was any evidence that Neanderthals had ever used coal. This is an interesting question, and one about which there is only little available information. In fact, there is almost no evidence of Neanderthals using coal, but the proof that does exist is very intriguing. The single instance comes from the Mousterian site of Les Canalettes, France (dating to ca. 73,500 years BP), where the structure of some of the charcoal recovered by archaeologists suggests Neanderthals exploited a local outcrop of coal. Originally (Théry et al. 1996), it was suggested that Neanderthals at the site used coal (lignite) during periods when firewood might have been less abundant, that is when forest cover shrank. A few years later, however, the same authors was determined that trees would have always been sufficiently available around Les Canalettes, which indicates that Neanderthals purposefully exploited coal for a variety of potential reasons (Théry-Parisot and Meignen 2000). An English summary of this research (Goldberg and Sherwood 2006:29) concludes the following:

"Les Canalettes is a shelter in the Causse du Larzac region of France. It contains Mousterian remains dating to the last glacial, about 73.5 ka. Most interesting is the occurrence of what appears to be burned lignite, which was likely used as fuel and was available as close as 5–15 km from the site, well within the acquisition zone of raw materials. Analysis of wood remains in the site suggests that people used coal when wood was in short supply. Furthermore, experiments by Théry-Parisot demonstrated that the occupants were familiar with some of the burning characteristics of the fuel. For example, adding lignite to a fire which no longer exhibited flames added significantly to the burning duration, thus permitting rekindling of the fire at a much later stage and prolonging the ability to heat. In addition, the study found that a hearth mixed with dried wood and lignite, consumed 4 times less wood than a hearth simply using rotted wood. These results provide important insights, suggesting that Neanderthals exhibited a clear knowledge of the combustible properties for diverse fuels."

So, yes, there is evidence from a one site that Neanderthals used coal, and this evidence suggests they were fully aware of its combustible properties. However, so far it's only been found at one site, which suggests it wasn't a widespread behavior. So, it's not a ton of evidence, but it's certainly suggestive. What's especially interesting, however, is the fact that at Les Canalettes, Neanderthals were well aware of coal's properties. This indicates that, no matter where they lived, Neanderthals could develop a very thorough knowledge of the properties of the various resources that were available to them. Considering especially that Les Canalettes falls towards the later end of the Neanderthal timeline, it also fits in comfortably with the recent conclusions that Neanderthals by that time were regular fire-users, if not paleopyrotechnologists (say that ten times fast!), as based on the review of the evidence recently proposed by Roebroeks and Villa (2011).

Roebroeks W, & Villa P (2011). On the earliest evidence for habitual use of fire in Europe. Proceedings of the National Academy of Sciences of the United States of America, 108 (13), 5209-14 PMID: 21402905